OFFSET
0,3
FORMULA
G.f. satisfies: A(x) = A( [z/(1+z)]/A(x) )/(1+z) where z = sqrt(x).
EXAMPLE
A(x) = 1 + x + 2*x^2 + 5*x^3 + 15*x^4 + 48*x^5 + 163*x^6 + 573*x^7 +...
A([x/(1+x)]/A(x^2))/(1+x) = 1 + x^2 + 2*x^4 + 5*x^6 + 15*x^8 + 48*x^10 +...
PROG
(PARI) {a(n)=local(A=1+x); for(n=1, n, A=1/x*serreverse(x/((1+x)*subst(A, x, x^2+x*O(x^n))))); polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 21 2008
STATUS
approved